1. Field of the Invention
The present invention relates, generally, to a technology of nonferrous metallurgy, and more particularly, to a swirling column nozzle, a swirling column smelting equipment and a swirling column smelting method.
2. Description of the Related Art
Lead is an important fundamental industrial raw material. In a conventional lead smelting process, i.e. “sintering-blast furnace method”, the lead sulfide concentrate has to be sintered in a separate sintering workshop. Meanwhile, to obtain suitable sintered briquette, a large amount of sintered concentrate has to be returned, which decreases production efficiency of lead smelting. Further, during sintering process of forming sintered briquette by desulfurization, the SO2 content in the sintering flue gases is relatively low, and there is difficulty in recovering sulfur. In addition, blast furnace smelting needs expensive smelter coke, which increases cost for producing pig lead. Therefore, the conventional sintering-blast furnace method may bring serious pollution to environment and consume large amount of energy.
To improve the conventional sintering-blast furnace method, Lurgi Company, Germany, developed a novel process, i.e. Queneau-Schuhmann-Lurgi process (Q.S.L. method) for direct lead smelting in 1970s. Presently, the Q.S.L. method is adopted by Stolberg smelting plant, Germany, and Onsan smelting plant for lead production. And it is characteristic of Q.S.L. method that the size of equipment needed is relatively small and pig lead can be directly obtained. However, the dust rate thereof is relatively high which may reach 20%. Further, the lead content in the furnace slag processed by Q.S.L. method is relatively high. Therefore, the production effect of the Q.S.L. method is not satisfactory.
In 1980s, nonferrous metal research institute of Soviet Union developed a direct lead smelting process, i.e., Kivcet method. The method has been industrialized by many plants, which is a novel lead smelting process with advanced indexes and high reliability. However, the Kivcet method has following disadvantages: the reaction furnace has a tetragonal shape with huge size and high producing cost. Further, electrodes have to be provided in the reaction furnace for reduction reaction, and the electrodes consume huge amounts of power. Still further, the Kivcet method has a large investment per product unit.
In addition, in the conventional lead smelting technologies, to obtain lead recovery rate which is sufficiently high, the slag produced after reaction in the furnace normally needs secondary slag cleaning, which means additional processing equipment. Thus, the processing cost thereof is increased and process complexity is increased accordingly.